In a blow to the 49ers defense, linebacker Aldon Smith has been suspended for season's first nine games

In a big blow to the San Francisco 49ers’ smothering defense, All-Pro outside linebacker Aldon Smith was suspended Friday for the first nine games of the season for violating the NFL’s personal conduct policy.

Smith, whose transgressions since 2012 include two DUI arrests and a felony weapons charge, is eligible to return Nov. 10. He has three days to appeal the suspension. In April he was arrested for allegedly making a false bomb threat at Los Angeles International Airport, though he was never charged.

After collecting 33½ sacks in his first two seasons, Smith missed five games in 2013 to seek treatment for a substance-abuse problem. He appeared in 11 games last season and finished with 8½ sacks.

The 49ers were already dealing with the loss of All-Pro linebacker NaVorro Bowman, who is recovering from a devastating knee injury suffered in the NFC championship game at Seattle.

The St. Louis Rams can breathe a sigh of relief, because Smith will miss both games against them. He will be available for both games against defending Super Bowl champion Seattle, however.